Forcing Black to advance the pawn to e5 in order to protect d6.
7... a7a6  8. a2a4 This is useful to prevent …b7-b5 after an exchange of pawns on d5. 8... d8e7 A new move. To be honest, I don't quite understand what advantage Black has in delaying the inevitable moves that are the exchange on d5 or 0-0. 9. d5e6 Aronian decides to exploit Black's move order. Taking the knight to g3 or f4 and then completing development is also playable. 9... f7e6 This capture is necessary, since it's not easy to defend the d6-pawn after